With the increasingly prominent issues of energy shortages and environmental protection, the research on spacecraft drag reduction has attracted widespread attention from industrialists. Surface microgrooves can effectively reduce the friction of spacecraft walls, which can be manufactured by a nanosecond laser. However, the machining process of nanosecond laser is affected by the coupling of multiple process parameters, and the processing morphology is difficult to recognize, restricting the high-precision processing of microgrooves. Therefore, accurate identification of nanosecond laser processing morphology is a prerequisite for ensuring the drag reduction performance of spacecraft. In this study, TC4 titanium alloy that is the aviation material is used as the research object, and the finite element model (FE model) for nanosecond laser processing is established. In this model, the nanosecond laser obeys the Gaussian distribution in time and space. In addition, thermal conduction, thermal convection, and thermal radiation are considered in the model. The rapid phase change of the material during laser processing is realized by using a significant convection coefficient, and finally processing profile is simulated by the deformation geometry technology. To improve the calculation efficiency of the FE model, the pulsed laser is equivalently processed, which significantly improves the computational efficiency. The prediction accuracy of the processing profile is improved, where the FE model is revised based on the experimental data. The relative error between the simulated depth and the machining depth is less than 9%. More importantly, the simulated morphology is in good agreement with the experimental data. The validity and reliability of the FE model are verified, which can guide nanosecond laser processing of microgrooves. Further, the proposed pulsed laser equivalent method and the model correction method will promote the three-dimensional simulation process of ultrafast lasers.

随着能源短缺和环境保护问题的日益突出，航天器减阻研究受到了工业界的广泛关注。表面微槽可以有效减少航天器壁面的摩擦，可以用纳秒激光制造。然而，纳秒激光加工过程受多个工艺参数耦合影响，加工形貌难以识别，制约了微槽的高精度加工。因此，准确识别纳秒激光加工形貌是保证航天器减阻性能的前提。本研究以航空材料TC4钛合金为研究对象，建立了纳秒激光加工的有限元模型（FE模型）。在这个模型中，纳秒激光在时间和空间上服从高斯分布。此外，模型中还考虑了热传导、热对流和热辐射。利用显着的对流系数实现激光加工过程中材料的快速相变，最终通过变形几何技术模拟加工轮廓。为提高有限元模型的计算效率，对脉冲激光进行了等效处理，显着提高了计算效率。根据实验数据修正有限元模型，提高了加工剖面的预测精度。模拟深度与加工深度的相对误差小于9%。更重要的是，模拟的形态与实验数据吻合良好。验证了有限元模型的有效性和可靠性，可指导微槽纳秒激光加工。此外，所提出的脉冲激光等效方法和模型校正方法将推动超快激光器的三维仿真过程。